Ultrabook Buyer’s Guide: Best Laptops for External GPU

As we’ve gained a better understanding of Thunderbolt 3 (TB3) eGPU enclosures, the unknown rests on the performance of the Thunderbolt 3 host computer. Thin and light ultrabooks are often a top choice to pair with an external GPU. This article serves as a buyer’s guide for choosing the best ultrabook to get the most out of a TB3 eGPU. The particular setup I’m using is an early 2018 Razer Blade Stealth with the Razer Core V2. This pairing is one of the highest performing TB3 ultrabook + eGPU setups as of Q1 2018. The Razer Blade Stealth shares many fundamental components with a handful of other Thunderbolt 3 ultrabooks that we will explore below.

Intel Thunderbolt Technology website has a list of certified Thunderbolt products. You can visit this link to find Thunderbolt 3 laptops currently available on the market. The multitude of choices can be overwhelming. Yet the specifications we’re most interested in for external graphics use are not readily available. So what are the criteria you should consider when choosing the best ultrabook for external graphics pairing? Through hundreds of implementations and build guides, we’ve distinguished three key features:

ULV CPU

For this buyer’s guide, we’re focusing on the newest crop of ultrabooks with Thunderbolt 3 connectivity. They now sport the Intel 8th generation quad-core ULV processors, doubling the core count of the previous generation. The top turbo speed is dependent on both the CPU workload and the ultrabook’s cooling system. If nearing the limits of TDP and CPU junction temperature (95˚-105˚ C), the CPU will throttle down performance. Thin, light systems are more than skin deep.

With nearly identical architecture to the previous generation, the 8th generation ULV CPU offers performance improvements by running double the number of cores, often at a more efficient reduced speed to maintain limits and thereby giving greater overall workload. These ultrabooks are the first revision with quad-core processors and should be future-proof for the next few years. At this time, the i7-8550U configuration was the highest performing, readily available ULV CPU.

PCIe Lanes

Thunderbolt connection allows at most 4 PCI Express lanes between the host and the device. In a ULV CPU ultrabook, this means allocating 4 out of a maximum 12 PCIe lanes. There are several peripheral components inside a laptop that make use of these high-speed interconnect lanes. For a typical ultrabook the NVMe flash storage drive gets a x4 PCIe connection. The Wireless card and other components may use a few x1 PCIe connections. If there’s a discrete graphics card, it will consume another x4 PCIe connection. Resource allocation conflicts arise when PC manufacturers decide how best to use these 12 lanes. Due to Thunderbolt 3 connectivity being a relatively new standard, Thunderbolt 3 ports are often not top priority.

One performance hindrance is a x2 PCIe 3.0 via Thunderbolt 3 connection. This is applicable for most single TB3-port ultrabooks, the Razer Blade Stealth being the exception. The Dell XPS 13 is perhaps one of the most popular ultrabooks in the past few years. Many aim to use it with an eGPU, but it’s been plagued with only 2 lanes for its sole Thunderbolt 3 port. The good news is things are gradually changing with the emergence of Thunderbolt 3 external graphics solutions. At CES 2018 I had a discussion regarding this with Gary L., a Dell system engineer. He confirmed the latest 2018 XPS 13 9370 now provides 4 PCIe lanes for its dual Thunderbolt 3 ports.

The HWiNFO64 screen capture on the left shows PCIe configuration in the early 2018 Razer Blade Stealth. The PCI Express Root Port #5 [A1/C1] attaches to a x4 connection that connects to the Thunderbolt 3 [Alpine Ridge] controller. This controller then hosts a single Thunderbolt 3 port. We also see PCI Express Root Port #3 [A1/C1] attaches to the Killer Wireless-n/a/ac 1535 Network Adapter. Last but not least, PCI Express Root Port #9 [A1/C1] attaches to a Samsung NVMe 960 controller. The HWiNFO64 screen capture (on the right) of a Dell XPS 9360 shows its inferior x2 PCIe connection to the Thunderbolt 3 controller.

OPI Mode

An infrequently discussed feature is the On Package DMI interconnect Interface (OPI). ULV processors such as the i7-8550U use OPI because, unlike HQ or HK processors, it lacks the Direct Media Interface (DMI 3.0) to facilitate communication between the PCH and CPU. The system designers can choose to either extract the most performance or optimize energy consumption on these ULV processors. OPI 2GT/s is ideal for extended mobile use at low-power tasks, while OPI 4GT/s is excellent for high-performance applications. These two OPI modes operate at a max theoretical throughput of 20Gbps and 40Gbps respectively. When you consider Intel’s claim of 40Gbps bandwidth for Thunderbolt 3 connectivity, it makes total sense OPI 4GT/s is the more appropriate choice for eGPU use.

Unfortunately the OPI settings are not something users can change at their convenience. The settings are baked into the system firmware/BIOS. At the moment PC manufacturers do not disclose the OPI mode in their marketing information. The only way to find out is to run performance tests yourself. If the ultrabook has an NVMe storage controller, read speed should exceed 1,800 MB/s in benchmark software such as ATTO to confirm the laptop is set to OPI 4GT/s.

As seen in the AIDA64 benchmarks above, OPI 4GT/s systems can extract the most out of Thunderbolt 3 eGPU. Keep in mind that Intel caps the throughput in these eGPU enclosures at roughly 22Gbps to preserve bandwidth for DisplayPort transmission over Thunderbolt 3. As external graphics adoption and demand grows, we hope Intel and partners dedicate more resources to optimize Thunderbolt 3 performance in general and external graphics use in specific.

Best Ultrabooks

Below are the best ultrabooks with the trinity of performance specs to host an external GPU. If you have an Intel 8th gen quad-core ultrabook not in this list and can confirm x4 PCIe + OPI 4GT/s, please share your findings by posting a build guide in our forum. We’ll keep this list up-to-date with user reports.

Lenovo X1 Carbon

$2,099

Want more performance?

Intel released 8th-generation 6-core (hex) Q 45W CPUs. These come packaged in laptops with larger chassis to accommodate more substantial cooling systems, coupled with bulkier power supplies to drive them. A bigger package that packs a bigger punch. It’s definitely worth the performance advantage if you can trade portability for performance.

Older notebook options?

eGPU.io user builds listed as 32Gbps-TB3 are confirmed to offer full Thunderbolt 3 bandwidth performance. At the link below, you can select LCD, CPU and then review the System Brand and Model widget for options to consider. Proceed to review user builds with your targeted system.

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Well written guide! I am excited to see the recent development with eGPUs. My next laptop will definitely be a thin and light laptop with an eGPU. Personally I hope Apple will release a 13″ MBP with 4-core CPU in the near future (Or even 6-core 15″) with native eGPU support.

Very informative article , but it does leave me with some questions. About the pcie lanes since there are 12 total if I was going to purchase a ultrabook 2-in-1 with a dedicated graphics card would it be better to get a SATA3 ssd instead of an NVMe(because NVME takes up x4 pcie lanes). I only ask because of the upcoming ASUS Zenbook Flip 15 (i7-8550u, 16gb ram ddr4, GTX1050) UX561UD. It gives the option of and HDD, sata3 ssd, or a pcie ssd instead. Does a sata3 ssd take up any pcie lanes? This leaves me to wonder if… Read more »

USB C is provided by the Thunderbolt circuit as far as I know so we don’t need separate lanes. Indeed the laptop you linked has two Thunderbolt 3 ports which makes 4 PCIe lanes a hard requirement. The laptop either connected the GPU over x2 or the NVMe socket only has two lanes. My bet is on the latter — but the GPU wouldn’t be bottlenecked by x2, it’s only an 1050.

I have my doubts over these latest gen CPU’s too, most games favour clock speed over core and I imaging the extra cores mean more heat and quicker throttling. Of course thats all just guess work from me, going to try to look up some comparison benchmarks…

The truth is that x2 vs x4 only matters if someone wants to use an 1070 or faster to accelerate the internal display. Otherwise, you could pick anything. I am trying to spread this information but it’s an uphill battle with articles like this.

@chx if you get to choose between a TB3 system with x2 PCIe and another with x4 PCIe, which one would you pick? I’m in MN and there’s a lot of snow on the ground this past week. Most of the 4-5 month long winter, the roads are rather nice and dry. I don’t get to see the benefits of snow tires very often. When I do, it’s significantly better than all-season tires. This article serves as a buying reference to pick the best ultrabook for eGPU use. It’s not reasonable to put an asterisk saying x2 PCIe does not… Read more »

Even if you have a game which mismanages cores/multithreading, Windows has a processor affinity mechanism in task manager that, err… manages this:

…and since the dual-core turbo-boost of 8th gen CPUs is actually considerably higher than 7th gen, there should be no reason why they would work not only as good as, but better than 7th gen CPUs. My experience in games and VR has been improved quite a bit by going from 7500U to 8550U. YMMV.

@laxlad The PCI lane allocation is a hardware (motherboard) thing, changing how the drive is connected will not change this, unless the laptop with the SATA drive physically doesn’t have the NVMe port (and has a different motherboard, which is unlikely). Normally the non-NVMe option exists to free that port for use with another device or make the HDD cheaper, I have not yet seen a single device where those lanes were allocated to TB3.

There are many different considerations when picking a laptop and Thunderbolt bandwidth is only one of them and if we would tell people to not bother with that unless X then their picking would be that much easier.

This article needs a first sentence saying “if you are using an external monitor then this article doesn’t apply, all of them are the same”. That’s all I am trying to say.

Thanks for the info guys. I didn’t clarify in my post but the reason I was concerned about the 4x pcie lanes because I plan on connecting an ssd and Ethernet connection to the egpu (mantiz Venus). from what I gather 4 lanes handle this better than 2. But if I were to just connect an egpu without any other peripherals I would be less concerned with 2 vs 4 lanes. Ownordisown in YouTube does a very good video showing the marginal difference between 2 vs 4 lanes when it comes to just using an egpu without connected peripherals. thankyou… Read more »

Greetings Very nice guide. I’m newbie here, this forum helped me a lot. Now I’m just curious why should i undervolting my i77500U (Blade Stealth) with i7500 to be able to play AC Origins on internal screen (1440p, high) on Razer Core v2 with evga 1080 sc. Is it my ultrabook CPU too weak on default setting to play it? Because on my i7 7700 HQ gaming laptop, i don’t need to close all running apps to run AC Origins with my Razer Core. Is there any gpu recommendation for UCPU, like price for performance for example? I have also… Read more »

You’re right it’s wrong to say TDP max is 15W, but it’s also misleading to say it can do sustained 25W, because that depends on the cooling architecture of the device. Most ultrabooks today will be doing 15W sustained with 25W Boost. CPUs nowadays actually have three (manufacturer provided) TDP modes of operation. This is not just about changing TDP wattage in XTU and such, these are actually distinct limits/modes of operation, with different guaranteed frequencies (c in cTDP for configurable), for example for the 8550U: (nominal) TDP: 15W (1.8GHz) cTDP up: 25W (2GHz) cTDP down: 10W (800MHz) The important… Read more »

Even those short bursts of 44W don’t come for free – you can see that the CPU hits 100C within seconds. Performance-wise, that’s fine, but it definitely won’t help silicon (and especially battery) degradation, and makes for a nice lap-warmer 🙂 In practical terms, if having a “cTDP up” device with x4 lanes is so important, what you’re saying is “I want a HQ chip” – where you get all the goodies – tons of cores, tons of PCI lanes, high minimum clocks. U chips never were about raw performance, but striking a good balance between battery life and performance.… Read more »

@4chip4 – you make some good points, here are my thoughts Even those short bursts of 44W don’t come for free – you can see that the CPU hits 100C within seconds. Performance-wise, that’s fine, but it definitely won’t help silicon (and especially battery) degradation, and makes for a nice lap-warmer Are you saying that Intel doesn’t properly design their CPUs or that lifespan will shorten if they are used this way? I’d love to see any data you have showing that designing Intel CPUs around Intel’s own power/thermal limits will result in shortened design lifespan. I am also assuming… Read more »

@ondert There are a few more laptops that should be good candidates just like the new LG Gram you mentioned. We’re waiting for actual implementation and confirmation that these laptops have x4 PCIe over TB3 as well as OPI 4GT/s before adding them onto the list.

Are you saying that Intel doesn’t properly design their CPUs or that lifespan will shorten if they are used this way? I’d love to see any data you have showing that designing Intel CPUs around Intel’s own power/thermal limits will result in shortened design lifespan. Umm, yes? Intel gives you a warranty, which is based on a statistical model. Silicon ages, and the degradation rate is correlated with both temperature and number of executed cycles even if you operate within the parameters. Intel does not know or has a say what the thermals will be in an OEM device. The… Read more »

We can agree to disagree on this one TANSTAAFL The double standard is somewhat amusing. Your HP laptop runs hotter you know; according to your long winded explanation of thermodynamics, your HP laptop probably lasts only 50% as long as the Dell 9370. All of what you just said basically said the Dell’s superior thermal solution and cooler operating temps make it an excellent choice 🙂 According to your link, since Dell laptop battery doesn’t get as hot as the spectre x360, it will last much longer 🙂 So based on all that, you should probably switch laptops asap!!!! In all… Read more »

@irev210 No, I *am* agreement that different design choices lead to different characteristics. What I didn’t agree with is that those design limitations are random or largely irrelevant (ie that bumping wattage is “free”). There is a reason why the same chips have different thermal and power limits – and it’s not that somebody just forgot to tick a box (regardless of who the manufacturer is). Here’s an example for the specific two devices you mentioned – x360s and XPSes do not have 1:1 the same target markets, it’s just that for eGPU uses we need to work backwards due… Read more »

Very helpful thank you! Two questions, first rather theoretical, TB3 right now supports up to 40GBps but we are only connecting 4PCIe 3rd gen lanes (4x8GBps), now would it be possible – or rather – useful to connect 5 or 6 PCIe lanes to a TB3 port? would that lower the performance drop we currently see on GPUs in cores? now secondly a very specific question: Is there a reason the MateBook X pro is not listed as a good device for eGPUs? Even so mobilTechReview states that the TB3 has 4 lanes there is still controversy about that is… Read more »

I am still searching for a laptop for my new setup and there are lots of questions i still have and things i would like to understand better then i do at the time, thanks to anyone who can clear some things up for me (sorry this will be a long post): uhm just a small note before i begin, @4chip4 you above mentioned the hp 13t as a replacement for the x360, from everything i could find the hp spectre 13t costs the same (in europe!) has less battery and the screen moves less, also the flex seems to be… Read more »

There are two more that might need consideration. 1. Samsung Notebook 9 15. You might think this would not be a contender, but a Windows Central reviewer stated it as 4-lane Thunderbolt 3 here: https://youtu.be/a2-h3E02mvQ?t=2m31s Even though it has an MX150 discrete GPU. I did a lot of investigation to try to get some clarification somewhere about this, and I found this nugget on the Notebookcheck review ( https://www.notebookcheck.net/Samsung-Notebook-9-NP900X5T-i7-8550U-GeForce-MX150-Laptop-Review.287284.0.html ). You would think with an MX150 dGPU that it would have a 4-lane implementation since that’s the physical wiring, but on inspection of this review it looks like the MX150… Read more »

I worked with an extremely helpful person over on the notebook review forums that owns a Samsung Notebook 9 15″ version with the MX150 dGPU and confirmed that the dGPU is in fact configured in x2 PCIe mode and that the x4 PCIe root port that has nothing connected to it seems to be the TB3 port. Things are getting exciting. Isn’t every i7-8550U laptop that has 4-lane Thunderbolt 3 also OPI 4GT/s? I thought the 8th Gen U CPUs all used OPI by default for their 12 lanes. Intel’s spec sheets seem to state this. Not sure why a… Read more »

I see that the HP Spectre x360 with an i7 processor has been mentioned in this list. I would like to buy an HP spectre but my budget allows me an i5 model only. Can someone please confirm if it would be eGPU compatible or not?

“Intel released 8th-generation 6-core (hex) Q 45W CPUs. These come packaged in laptops with larger chassis to accommodate more substantial cooling systems, coupled with bulkier power supplies to drive them. A bigger package that packs a bigger punch. It’s definitely worth the performance advantage if you can trade portability for performance.” Can someone clarify if that is indeed the case? I’ve read in several places that despite the expected performance gain, 8750H based systems don’t perform as well as 8550U based ones in eGPU scenarios. And if so, what might be the reason? Something related to the dGPU or perhaps… Read more »

Posted by: Ziggity “Intel released 8th-generation 6-core (hex) Q 45W CPUs. These come packaged in laptops with larger chassis to accommodate more substantial cooling systems, coupled with bulkier power supplies to drive them. A bigger package that packs a bigger punch. It’s definitely worth the performance advantage if you can trade portability for performance.” Can someone clarify if that is indeed the case? I’ve read in several places that despite the expected performance gain, 8750H based systems don’t perform as well as 8550U based ones in eGPU scenarios. And if so, what might be the reason? Something related to the… Read more »

@itsage
Very nice guide! I’m wondering if it is ok for me to translate this guide to Chinese and post it on chinese forums? Information of eGPU is very rare in Chinese community, and they could really use this well written guide. Of course I’ll leave the link to this page, give you the whole credit, and will not use it for business purposes.

One important thing to mention is that the CPUs on Macbook Pro are rated at 28W, compared to the 15W on other Windows PCs. This means a significant performance difference. Just go to CPU benchmark by PassMark and search for i7-8550U and i7-8559U and see what I mean.

Hey guys, I have been on this site quite a bit as I plan to buy a new laptop soon. I have a few questions about this post’s content I’m hoping you can answer: 1) are the laptops listed above for the model year 2018 or 2019? 2) I’m sure there are an infinite number of possible eGPU configs, do you know if there is a cost estimation tool to compare buying a laptop with a powerful GPU vs. an ultrabook + eGPU? For example: the MSI GS65 Stealth with RTX 2060 – 6Gb is $2300 vs. putting that money… Read more »

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6 months ago

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Matt

Hello, could you tell me if the new Dell XPS 13 is compatible, model number 9380? Also could you provide model numbers for the rest of the laptops, the amazon links are not clear as to the editions and newer versions. Thanks!

Great article, and I keep coming back to it when considering ultrabook/eGPU builds. However, it’s a little outdated, as the newest Whiskey Lake-U chips (i5-8265U/i7-8565U) actually have 16 PCIe 3.0 lanes, and should be able tohandle a full TB3 @ x4 and dGPU @ x4 at the same time. It would also be good to update the page to mention the model #/years/size on the recommended laptop list above. For example, the Lenovo Yoga 730 that this page suggests is the 13.3″ (730-15IKB), but that isn’t obvious from just reading it. There’s also the 730-15IKB w/ GTX 1050 doesn’t have… Read more »